X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=dns.c;h=3f508271672e19584fe1bbab230492d294ae8df5;hb=96c58e8ba51d67d1d90660ba8ff4f597c03688fe;hp=243c5a33c1703f2973664b92ac32fdba2a6fd275;hpb=4aa744ffac20c7b5e18cb3b23e5dbac8221c0043;p=catta

diff --git a/dns.c b/dns.c
index 243c5a3..3f50827 100644
--- a/dns.c
+++ b/dns.c
@@ -1,8 +1,11 @@
+#include <netinet/in.h>
+
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 
 #include "dns.h"
+#include "util.h"
 
 flxDnsPacket* flx_dns_packet_new(guint max_size) {
     flxDnsPacket *p;
@@ -15,6 +18,7 @@ flxDnsPacket* flx_dns_packet_new(guint max_size) {
     p = g_malloc(sizeof(flxDnsPacket) + max_size);
     p->size = p->rindex = FLX_DNS_PACKET_HEADER_SIZE;
     p->max_size = max_size;
+    p->name_table = NULL;
 
     memset(FLX_DNS_PACKET_DATA(p), 0, p->size);
     return p;
@@ -24,7 +28,7 @@ flxDnsPacket* flx_dns_packet_new_query(guint max_size) {
     flxDnsPacket *p;
 
     p = flx_dns_packet_new(max_size);
-    flx_dns_packet_set_field(p, DNS_FIELD_FLAGS, DNS_FLAGS(0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
+    flx_dns_packet_set_field(p, FLX_DNS_FIELD_FLAGS, FLX_DNS_FLAGS(0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
     return p;
 }
 
@@ -32,12 +36,16 @@ flxDnsPacket* flx_dns_packet_new_response(guint max_size) {
     flxDnsPacket *p;
 
     p = flx_dns_packet_new(max_size);
-    flx_dns_packet_set_field(p, DNS_FIELD_FLAGS, DNS_FLAGS(1, 0, 0, 0, 0, 0, 0, 0, 0, 0));
+    flx_dns_packet_set_field(p, FLX_DNS_FIELD_FLAGS, FLX_DNS_FLAGS(1, 0, 0, 0, 0, 0, 0, 0, 0, 0));
     return p;
 }
 
 void flx_dns_packet_free(flxDnsPacket *p) {
     g_assert(p);
+
+    if (p->name_table)
+        g_hash_table_destroy(p->name_table);
+    
     g_free(p);
 }
 
@@ -55,47 +63,104 @@ guint16 flx_dns_packet_get_field(flxDnsPacket *p, guint index) {
     return g_ntohs(((guint16*) FLX_DNS_PACKET_DATA(p))[index]);
 }
 
+/* Read the first label from string *name, unescape "\" and write it to dest */
+gchar *flx_unescape_label(gchar *dest, guint size, const gchar **name) {
+    guint i = 0;
+    gchar *d;
+    
+    g_assert(dest);
+    g_assert(size > 0);
+    g_assert(name);
+    g_assert(*name);
+
+    d = dest;
+    
+    for (;;) {
+        if (i >= size)
+            return NULL;
+
+        if (**name == '.') {
+            (*name)++;
+            break;
+        }
+        
+        if (**name == 0)
+            break;
+        
+        if (**name == '\\') {
+            (*name) ++;
+            
+            if (**name == 0)
+                break;
+        }
+        
+        *(d++) = *((*name) ++);
+        i++;
+    }
+
+    g_assert(i < size);
+
+    *d = 0;
+
+    return dest;
+}
+
 guint8* flx_dns_packet_append_name(flxDnsPacket *p, const gchar *name) {
-    guint8 *d, *f = NULL;
+    guint8 *d, *saved_ptr = NULL;
     guint saved_size;
     
     g_assert(p);
     g_assert(name);
 
     saved_size = p->size;
+    saved_ptr = flx_dns_packet_extend(p, 0);
+    
+    while (*name) {
+        guint n;
+        guint8* prev;
+        const gchar *pname;
+        gchar label[64];
 
-    for (;;) {
-        guint n = strcspn(name, ".");
-        if (!n || n > 63)
-            goto fail;
-        
-        if (!(d = flx_dns_packet_extend(p, n+1)))
-            goto fail;
+        /* Check whether we can compress this name. */
+
+        if (p->name_table && (prev = g_hash_table_lookup(p->name_table, name))) {
+            guint index;
             
-        if (!f)
-            f = d;
-        d[0] = n;
-        memcpy(d+1, name, n);
+            g_assert(prev >= FLX_DNS_PACKET_DATA(p));
+            index = (guint) (prev - FLX_DNS_PACKET_DATA(p));
 
-        name += n;
+            g_assert(index < p->size);
 
-        /* no trailing dot */
-        if (!*name)
-            break;
+            if (index < 0x4000) {
+                guint16 *t;
+                if (!(t = (guint16*) flx_dns_packet_extend(p, sizeof(guint16))))
+                    return NULL;
 
-        name ++;
+                *t = g_htons((0xC000 | index));
+                return saved_ptr;
+            }
+        }
 
-        /* trailing dot */
-        if (!*name)
-            break;
+        pname = name;
+        
+        if (!(flx_unescape_label(label, sizeof(label), &name)))
+            goto fail;
+
+        if (!(d = flx_dns_packet_append_string(p, label)))
+            goto fail;
+
+        if (!p->name_table)
+            p->name_table = g_hash_table_new_full((GHashFunc) flx_domain_hash, (GEqualFunc) flx_domain_equal, g_free, NULL);
+
+        g_hash_table_insert(p->name_table, g_strdup(pname), d);
     }
 
     if (!(d = flx_dns_packet_extend(p, 1)))
         goto fail;
     
-    d[0] = 0;
+    *d = 0;
 
-    return f;
+    return saved_ptr;
 
 fail:
     p->size = saved_size;
@@ -139,6 +204,25 @@ guint8 *flx_dns_packet_append_bytes(flxDnsPacket  *p, gconstpointer b, guint l)
     return d;
 }
 
+guint8* flx_dns_packet_append_string(flxDnsPacket *p, const gchar *s) {
+    guint8* d;
+    guint k;
+    
+    g_assert(p);
+    g_assert(s);
+
+    if ((k = strlen(s)) >= 255)
+        k = 255;
+    
+    if (!(d = flx_dns_packet_extend(p, k+1)))
+        return NULL;
+
+    *d = (guint8) k;
+    memcpy(d+1, s, k);
+
+    return d;
+}
+
 guint8 *flx_dns_packet_extend(flxDnsPacket *p, guint l) {
     guint8 *d;
     
@@ -153,25 +237,6 @@ guint8 *flx_dns_packet_extend(flxDnsPacket *p, guint l) {
     return d;
 }
 
-guint8 *flx_dns_packet_append_name_compressed(flxDnsPacket *p, const gchar *name, guint8 *prev) {
-    guint16 *d;
-    signed long k;
-    g_assert(p);
-
-    if (!prev)
-        return flx_dns_packet_append_name(p, name);
-    
-    k = prev - FLX_DNS_PACKET_DATA(p);
-    if (k < 0 || k >= 0x4000 || (guint) k >= p->size)
-        return flx_dns_packet_append_name(p, name);
-
-    if (!(d = (guint16*) flx_dns_packet_extend(p, sizeof(guint16))))
-        return NULL;
-    
-    *d = g_htons((0xC000 | k));
-    return prev;
-}
-
 gint flx_dns_packet_check_valid(flxDnsPacket *p) {
     guint16 flags;
     g_assert(p);
@@ -179,9 +244,9 @@ gint flx_dns_packet_check_valid(flxDnsPacket *p) {
     if (p->size < 12)
         return -1;
 
-    flags = flx_dns_packet_get_field(p, DNS_FIELD_FLAGS);
+    flags = flx_dns_packet_get_field(p, FLX_DNS_FIELD_FLAGS);
 
-    if (flags & DNS_FLAG_OPCODE || flags & DNS_FLAG_RCODE)
+    if (flags & FLX_DNS_FLAG_OPCODE || flags & FLX_DNS_FLAG_RCODE)
         return -1;
 
     return 0;
@@ -190,7 +255,43 @@ gint flx_dns_packet_check_valid(flxDnsPacket *p) {
 gint flx_dns_packet_is_query(flxDnsPacket *p) {
     g_assert(p);
     
-    return !(flx_dns_packet_get_field(p, DNS_FIELD_FLAGS) & DNS_FLAG_QR);
+    return !(flx_dns_packet_get_field(p, FLX_DNS_FIELD_FLAGS) & FLX_DNS_FLAG_QR);
+}
+
+/* Read a label from a DNS packet, escape "\" and ".", append \0 */
+static gchar *escape_label(guint8* src, guint src_length, gchar **ret_name, guint *ret_name_length) {
+    gchar *r;
+
+    g_assert(src);
+    g_assert(ret_name);
+    g_assert(*ret_name);
+    g_assert(ret_name_length);
+    g_assert(*ret_name_length > 0);
+
+    r = *ret_name;
+
+    while (src_length > 0) {
+        if (*src == '.' || *src == '\\') {
+            if (*ret_name_length < 3)
+                return NULL;
+            
+            *((*ret_name) ++) = '\\';
+            (*ret_name_length) --;
+        }
+
+        if (*ret_name_length < 2)
+            return NULL;
+        
+        *((*ret_name)++) = *src;
+        (*ret_name_length) --;
+
+        src_length --;
+        src++;
+    }
+
+    **ret_name = 0;
+
+    return r;
 }
 
 static gint consume_labels(flxDnsPacket *p, guint index, gchar *ret_name, guint l) {
@@ -236,10 +337,10 @@ static gint consume_labels(flxDnsPacket *p, guint index, gchar *ret_name, guint
             } else
                 first_label = 0;
 
-            memcpy(ret_name, FLX_DNS_PACKET_DATA(p) + index, n);
+            if (!(escape_label(FLX_DNS_PACKET_DATA(p) + index, n, &ret_name, &l)))
+                return -1;
+
             index += n;
-            ret_name += n;
-            l -= n;
             
             if (!compressed)
                 ret += n;
@@ -310,10 +411,38 @@ gint flx_dns_packet_consume_bytes(flxDnsPacket *p, gpointer ret_data, guint l) {
     return 0;
 }
 
+gint flx_dns_packet_consume_string(flxDnsPacket *p, gchar *ret_string, guint l) {
+    guint k;
+    
+    g_assert(p);
+    g_assert(ret_string);
+    g_assert(l > 0);
+
+    if (p->rindex >= p->size)
+        return -1;
+
+    k = FLX_DNS_PACKET_DATA(p)[p->rindex];
+
+    if (p->rindex+1+k > p->size)
+        return -1;
+
+    if (l > k+1)
+        l = k+1;
+
+    memcpy(ret_string, FLX_DNS_PACKET_DATA(p)+p->rindex+1, l-1);
+    ret_string[l-1] = 0;
+
+    
+    p->rindex += 1+k;
+
+    return 0;
+    
+}
+
 gconstpointer flx_dns_packet_get_rptr(flxDnsPacket *p) {
     g_assert(p);
     
-    if (p->rindex >= p->size)
+    if (p->rindex > p->size)
         return NULL;
 
     return FLX_DNS_PACKET_DATA(p) + p->rindex;
@@ -330,65 +459,140 @@ gint flx_dns_packet_skip(flxDnsPacket *p, guint length) {
 }
 
 flxRecord* flx_dns_packet_consume_record(flxDnsPacket *p, gboolean *ret_cache_flush) {
-    gchar name[257], buf[257+6];
+    gchar name[257], buf[257];
     guint16 type, class;
     guint32 ttl;
     guint16 rdlength;
     gconstpointer data;
+    flxRecord *r = NULL;
+    gconstpointer start;
 
     g_assert(p);
     g_assert(ret_cache_flush);
 
+/*     g_message("consume_record()"); */
+
     if (flx_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
         flx_dns_packet_consume_uint16(p, &type) < 0 ||
         flx_dns_packet_consume_uint16(p, &class) < 0 ||
         flx_dns_packet_consume_uint32(p, &ttl) < 0 ||
-        flx_dns_packet_consume_uint16(p, &rdlength) < 0)
-        return NULL;
+        flx_dns_packet_consume_uint16(p, &rdlength) < 0 ||
+        p->rindex + rdlength > p->size)
+        
+        goto fail;
+
+/*     g_message("name = %s, rdlength = %u", name, rdlength); */
 
+    *ret_cache_flush = !!(class & FLX_DNS_CACHE_FLUSH);
+    class &= ~ FLX_DNS_CACHE_FLUSH;
+    
+    start = flx_dns_packet_get_rptr(p);
+    
+    r = flx_record_new_full(name, class, type);
+    
     switch (type) {
         case FLX_DNS_TYPE_PTR:
         case FLX_DNS_TYPE_CNAME:
+
+/*             g_message("ptr"); */
+            
             if (flx_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
-                return NULL;
+                goto fail;
+
+            r->data.ptr.name = g_strdup(buf);
+            break;
+
+            
+        case FLX_DNS_TYPE_SRV:
+
+/*             g_message("srv"); */
+            
+            if (flx_dns_packet_consume_uint16(p, &r->data.srv.priority) < 0 ||
+                flx_dns_packet_consume_uint16(p, &r->data.srv.weight) < 0 ||
+                flx_dns_packet_consume_uint16(p, &r->data.srv.port) < 0 ||
+                flx_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
+                goto fail;
             
-            data = buf;
-            rdlength = strlen(buf);
+            r->data.srv.name = g_strdup(buf);
             break;
 
-        case FLX_DNS_TYPE_SRV: {
-            const guint8 *t = flx_dns_packet_get_rptr(p);
+        case FLX_DNS_TYPE_HINFO:
+            
+/*             g_message("hinfo"); */
+
+            if (flx_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
+                goto fail;
 
-            if (flx_dns_packet_skip(p, 6) < 0)
-                return NULL;
+            r->data.hinfo.cpu = g_strdup(buf);
+
+            if (flx_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
+                goto fail;
+
+            r->data.hinfo.os = g_strdup(buf);
+            break;
+
+        case FLX_DNS_TYPE_TXT:
+
+/*             g_message("txt"); */
+
+            if (rdlength > 0) {
+                r->data.txt.string_list = flx_string_list_parse(flx_dns_packet_get_rptr(p), rdlength);
+                
+                if (flx_dns_packet_skip(p, rdlength) < 0)
+                    goto fail;
+            } else
+                r->data.txt.string_list = NULL;
             
-            memcpy(buf, t, 6);
+            break;
 
-            if (flx_dns_packet_consume_name(p, buf+6, sizeof(buf)-6) < 0)
-                return NULL;
+        case FLX_DNS_TYPE_A:
 
-            data = buf;
-            rdlength = 6 + strlen(buf+6);
+/*             g_message("A"); */
+
+            if (flx_dns_packet_consume_bytes(p, &r->data.a.address, sizeof(flxIPv4Address)) < 0)
+                goto fail;
+            
+            break;
+
+        case FLX_DNS_TYPE_AAAA:
+
+/*             g_message("aaaa"); */
+            
+            if (flx_dns_packet_consume_bytes(p, &r->data.aaaa.address, sizeof(flxIPv6Address)) < 0)
+                goto fail;
+            
             break;
-        }
             
         default:
 
+/*             g_message("generic"); */
+            
             if (rdlength > 0) {
 
-                if (!(data = flx_dns_packet_get_rptr(p)) ||
-                    flx_dns_packet_skip(p, rdlength) < 0)
-                    return NULL;
-            } else
-                data = NULL;
+                r->data.generic.data = g_memdup(flx_dns_packet_get_rptr(p), rdlength);
+                
+                if (flx_dns_packet_skip(p, rdlength) < 0)
+                    goto fail;
+            }
 
             break;
     }
 
-    *ret_cache_flush = !!(class & MDNS_CACHE_FLUSH);
-    class &= ~ MDNS_CACHE_FLUSH;
+/*     g_message("%i == %u ?", (guint8*) flx_dns_packet_get_rptr(p) - (guint8*) start, rdlength); */
+    
+    /* Check if we read enough data */
+    if ((guint8*) flx_dns_packet_get_rptr(p) - (guint8*) start != rdlength)
+        goto fail;
+    
+    r->ttl = ttl;
+
+    return r;
 
-    return flx_record_new_full(name, class, type, data, rdlength, ttl);
+fail:
+    if (r)
+        flx_record_unref(r);
+
+    return NULL;
 }
 
 flxKey* flx_dns_packet_consume_key(flxDnsPacket *p) {
@@ -402,74 +606,143 @@ flxKey* flx_dns_packet_consume_key(flxDnsPacket *p) {
         flx_dns_packet_consume_uint16(p, &class) < 0)
         return NULL;
 
-    class &= ~ MDNS_CACHE_FLUSH;
+    class &= ~ FLX_DNS_CACHE_FLUSH;
 
     return flx_key_new(name, class, type);
 }
 
 guint8* flx_dns_packet_append_key(flxDnsPacket *p, flxKey *k) {
     guint8 *t;
+    guint size;
     
     g_assert(p);
     g_assert(k);
 
+    size = p->size;
+    
     if (!(t = flx_dns_packet_append_name(p, k->name)) ||
         !flx_dns_packet_append_uint16(p, k->type) ||
-        !flx_dns_packet_append_uint16(p, k->class))
+        !flx_dns_packet_append_uint16(p, k->class)) {
+        p->size = size;
         return NULL;
+    }
 
     return t;
 }
 
 guint8* flx_dns_packet_append_record(flxDnsPacket *p, flxRecord *r, gboolean cache_flush) {
-    guint8 *t;
+    guint8 *t, *l, *start;
+    guint size;
 
     g_assert(p);
     g_assert(r);
 
+    size = p->size;
+
     if (!(t = flx_dns_packet_append_name(p, r->key->name)) ||
         !flx_dns_packet_append_uint16(p, r->key->type) ||
-        !flx_dns_packet_append_uint16(p, cache_flush ? (r->key->class | MDNS_CACHE_FLUSH) : (r->key->class &~ MDNS_CACHE_FLUSH)) ||
-        !flx_dns_packet_append_uint32(p, r->ttl))
-        return NULL;
+        !flx_dns_packet_append_uint16(p, cache_flush ? (r->key->class | FLX_DNS_CACHE_FLUSH) : (r->key->class &~ FLX_DNS_CACHE_FLUSH)) ||
+        !flx_dns_packet_append_uint32(p, r->ttl) ||
+        !(l = flx_dns_packet_append_uint16(p, 0)))
+        goto fail;
+
+    start = flx_dns_packet_extend(p, 0);
 
     switch (r->key->type) {
         
         case FLX_DNS_TYPE_PTR:
-        case FLX_DNS_TYPE_CNAME: {
-            char ptr_name[257];
+        case FLX_DNS_TYPE_CNAME :
 
-            g_assert((size_t) r->size+1 <= sizeof(ptr_name));
-            memcpy(ptr_name, r->data, r->size);
-            ptr_name[r->size] = 0;
+            if (!(flx_dns_packet_append_name(p, r->data.ptr.name)))
+                goto fail;
             
-            if (!flx_dns_packet_append_uint16(p, strlen(ptr_name)+1) ||
-                !flx_dns_packet_append_name(p, ptr_name))
-                return NULL;
+            break;
+
+        case FLX_DNS_TYPE_SRV:
+
+            if (!flx_dns_packet_append_uint16(p, r->data.srv.priority) ||
+                !flx_dns_packet_append_uint16(p, r->data.srv.weight) ||
+                !flx_dns_packet_append_uint16(p, r->data.srv.port) ||
+                !flx_dns_packet_append_name(p, r->data.srv.name))
+                goto fail;
 
             break;
-        }
 
-        case FLX_DNS_TYPE_SRV: {
-            char name[257];
+        case FLX_DNS_TYPE_HINFO:
+            if (!flx_dns_packet_append_string(p, r->data.hinfo.cpu) ||
+                !flx_dns_packet_append_string(p, r->data.hinfo.os))
+                goto fail;
 
-            g_assert(r->size >= 6 && (size_t) r->size-6+1 <= sizeof(name));
-            memcpy(name, r->data+6, r->size-6);
-            name[r->size-6] = 0;
+            break;
 
-            if (!flx_dns_packet_append_uint16(p, strlen(name+6)+1+6) ||
-                !flx_dns_packet_append_bytes(p, r->data, 6) ||
-                !flx_dns_packet_append_name(p, name))
-                return NULL;
+        case FLX_DNS_TYPE_TXT: {
+
+            guint8 *data;
+            guint size;
 
+            size = flx_string_list_serialize(r->data.txt.string_list, NULL, 0);
+
+/*             g_message("appending string: %u %p", size, r->data.txt.string_list); */
+
+            if (!(data = flx_dns_packet_extend(p, size)))
+                goto fail;
+
+            flx_string_list_serialize(r->data.txt.string_list, data, size);
             break;
         }
 
+
+        case FLX_DNS_TYPE_A:
+
+            if (!flx_dns_packet_append_bytes(p, &r->data.a.address, sizeof(r->data.a.address)))
+                goto fail;
+            
+            break;
+
+        case FLX_DNS_TYPE_AAAA:
+            
+            if (!flx_dns_packet_append_bytes(p, &r->data.aaaa.address, sizeof(r->data.aaaa.address)))
+                goto fail;
+            
+            break;
+            
         default:
-            if (!flx_dns_packet_append_uint16(p, r->size) ||
-                (r->size != 0 && !flx_dns_packet_append_bytes(p, r->data, r->size)))
-                return NULL;
+
+            if (r->data.generic.size &&
+                flx_dns_packet_append_bytes(p, r->data.generic.data, r->data.generic.size))
+                goto fail;
+
+            break;
     }
 
+
+
+    
+    size = flx_dns_packet_extend(p, 0) - start;
+    g_assert(size <= 0xFFFF);
+
+/*     g_message("appended %u", size); */
+
+    * (guint16*) l = g_htons((guint16) size);
+    
     return t;
+
+
+fail:
+    p->size = size;
+    return NULL;
+}
+
+gboolean flx_dns_packet_is_empty(flxDnsPacket *p) {
+    g_assert(p);
+
+    return p->size <= FLX_DNS_PACKET_HEADER_SIZE;
+}
+
+guint flx_dns_packet_space(flxDnsPacket *p) {
+    g_assert(p);
+
+    g_assert(p->size <= p->max_size);
+    
+    return p->max_size - p->size;
 }